Jab 170 Handling update

[Vev]

This was posted on the Jab site regarding upgrades to rudder peddles and fitting a new ventral fin.

 

http://www.jabiru.net.au/Service%20Bulletins/Airframe%20Files/JSB029-1J170.pdf

 

Cheers

 

Vev

 

 

[Ultralights]

thats one large vertical fin! tail strike heaven

 

 

[Vev]

I should have also mention there is a new mod to reduce flap defection too .....

 

Cheers

 

Vev

 

 

[Thirsty]

It says in the bulletin that this is a mandatory mod for all 170's within 300 hours?? How bad is the 170 now? And why just the 170 - why not the 160? Isn't the only difference the longer wing span on the 170?

 

 

[dazza 38]

Thats the key i think Thirsty, the long span wings.

 

 

[winsor68]

Thank goodness. Now if they just put a bigger motor in it.... Even to my inexperienced hands the one I flew felt mushy until it well and truly got on step.

 

 

[alf jessup]

Jesus, youd think theyd atleast use the foxbat idea and chuck a little wheel in there to help protect it...

Maybe just whack a set of floats on it as it seems to have a decent water rudder now.

 

 

[winsor68]

So.... I guess anyone who has flown a J170 can now use the title "Test Pilot" in their posts? Good on you Jabiru.

 

 

[turboplanner]

Well, well, well....anyone who has experienced an "out of rudder authority" when a gust hits the flap on one wing will really appreciate these changes.

 

 

[Vev]

I am more than happy with the handling and performance of my J170... Being a manditory mod, what happens if I choose NOT to implement it?

Jabiru says

 

Compliance – Implementation Schedule

 

 The changes detailed within this Bulletin are mandatory for all J170 aircraft. They must be carried out within the next 300 hours of flight or within 12 months of the date of issue of this Bulletin – whichever is the sooner.

 

Hi Donkey,

 

I wouldn't second guess a manufactures written safety directive unless I had something in writing saying you can .... I'm sure your insurance wouldn't hesitate to write you off .... I would also hate to think what sort of a defence you would put up in front of a court should a passenger get hurt or worse!

 

If you are in doubt about the benefits, give Jab a call.

 

Cheers

 

Vev

 

 

[facthunter]

Clearly this would not have happened IF it wasn't necessary. There must be some situation that has occurred to warrant this mod. It is a good thing that it has been done. Lots of aircraft have strakes fins etc added after they are put in service. eg F-27. P-51 Skyranger....plus many others. Nev

 

 

[turboplanner]

We had a long thread on this, with many confused about the difference in Jab models.

 

The J170 has long wings and a short fuse, so the moment arm from the flap is larger vs the moment arm from the fin

 

If you are flaring with full flap in a crosswind with the upwind wing down, and compensating rudder on, and a quartering gust hits you, it will drag a wing back which turns the aircraft very quickly, and you'll run out of rudder authority - a very difficult situation if you've just touched the wheels or are about to, because the aircraft will be pointing diagonally to the strip.

 

Most pilots have never experienced this combination, but like wind shear, it's sitting out there one day to bite you when you least expect it.

 

Since gusts are not visible, and not predictable, these modifications have the potential to save runway excursions, and serious damage.

 

 

[facthunter]

Well put Turbo. Nev

 

 

[Ballpoint 246niner]

My previous post on this....

 

"Hey Bob , my understanding is they're trying the longer nose to get the CG fwd with the extended engine mounts so they can use the generous luggage area and the 600kg MTOW to allow more luggage to be carried in the aft cg position. Changing the nose to the longer cone as on my 120 means they have to redistribute the longitudinal forces- particularly in spin recovery, so hence the larger tail- also will increase the rudder authority, something jabs are a bit short on. You may have seen the dataloggers and telltales all over it- part of the testing requirements for re-certification."

 

They have been working on this since returning from Natfly last year. I know many folks often communicate the factory is deaf to all the discussions that go on about their aircraft but they do hear it all. They just don't respond to everything. for that we are often bestowed with self imposed title of Judge- Jury and executioner.

 

100hp in a Jab 4 cylinder would be great though -especially when they hold together:oh yeah:

 

 

[djpacro]

VH LSA Only

 

I am more than happy with the handling and performance of my J170... Being a manditory mod, what happens if I choose NOT to implement it?

A good question.My response only applies to LSA's with VH registration.

This CASA Advisory Circular explains the use of Safety Directions issued by the manufacturer and CASA's lack of interest in issuing AD's for LSAs.

 

Failure to comply with a SD is considered a serious breach of the regulations and could result in regulatory action

 

 

Personally, I would definitely go for any Service Bulletin from a manufacturer even suggesting that more tail area is good. I've always said that you can never have too much fin area. Seems to be some good technical advice in the other posts.

 

 

[Guest Kevin the Penniless]

How much is this mod (including labour) going to cost? If a car is out there with a 'design fault' then the manufacturer pays for the 'recall' I think Jabiru should cover all costs. My J170 has only 50 hours on the clock and handles fine (including crosswinds). I will be complaining to Jabiru and urge every owner to do the same and ask for the reasons behind the mods. The service bulletin is too vauge. I am quite *issed off about this.

 

 

[Guest Kevin the Penniless]

I have sent Jabiru a letter (email) asking why, if the mods are 'to make handling easier' for the pilot rather than fix a safety problem they have to make the modifications mandatory. I am happy with the way my J170 handles and don't want to be stuffing around with it. I think the bulletin is very poorly prepared. It should be a non-mandatory bulletin. They even mention they tested one aircraft - big deal, I have flown a bunch of different Jabs and they all have slightly different handling. Very annoyed here. Who's going to pay for this mod? (Off stomping around now....)

 

 

[turboplanner]

I have sent Jabiru a letter (email) asking why, if the mods are 'to make handling easier' for the pilot rather than fix a safety problem they have to make the modifications mandatory. I am happy with the way my J170 handles and don't want to be stuffing around with it. I think the bulletin is very poorly prepared. It should be a non-mandatory bulletin. They even mention they tested one aircraft - big deal, I have flown a bunch of different Jabs and they all have slightly different handling. Very annoyed here. Who's going to pay for this mod? (Off stomping around now....)

Sounds like you haven't experienced the issue Kevin. I wouldn't expect to find any problem with steady crosswinds either, but that's not what we were talking about.

 

 

[Spin]

Yea Gods, that is a fair chunk of hardware to add to the poor little Jab. Strikes me that if a lack of rudder authority was the problem, they should be adding area to the rudder surface, not to the fixed fin? Surely adding a fixed strake is only going to exacerbate a weathercocking tendency, as per the example given?

 

From my admittedly limited Jab experience (and not in a J170 either) I would have liked more rudder - but then I actually like to use my feet and even the Tecnams could do with more imo. Now a Cub....:big_grin:

 

I'm inclined to agree with you Kevin, if Holden called me and said that my new ute needed a different spring assembly to make it less liable to wag its tail - and I had to fit it by the next service, I'd be looking to them to pay for the mod too. If I were you I'd be quietly keeping up the pressure on them and when they knock you back, take a trundle along to the local consumer tribunal with your paperwork - aircraft manufacturers operate in exactly the same consumer legal environment as any other Australian business and I'm willing to bet they would come second in that argument.

 

 

[facthunter]

maybe they would come second in that argument. Lawyers put the big three out of the skies in America for years and added to the price of every aeroplane sold, a component to cover liability claims. IF you want to pay more for the planes you buy, start sueing... It will happen. jabiru have found a problem with a plane in service, that, after correction, makes their plane handle better. Isn't this a GOOD thing? Would you rather they just changed the later models and kept quiet? That would hardly be a responsible position to adopt, and Kevin, would it be a responsible thing for you to do either?. The world of flying is a lot different from many earth-bound pursuits. No aircraft is ever perfect, Faults ARE found in service and by being acted upon we all get a safer scene. Collectively... Nev

 

 

[Spin]

Nev that is an emotional response with little basis in fact, the litigation environment in the US that all but put the big three out of business is very different to our consumer protection legislation. US juries were giving punitive damages into the tens and hundreds of millions of dollars - as in the case of a '48 Piper Cub where a widow sued because it had only a lap strap seatbelt and a 3 or more point harness would have protected her husband better. The fact that he may or may not have even been wearing the strap, flew into cloud and came out in a vertical dive before impacting terra firma was of lesser importance! Ridiculous by any measure, but not analygous to our situation.

 

 

[facthunter]

Just putting a point of view that I think should be put. It doesn't hurt to get a different slant on things. the "other" side of the coin so to speak. When a course of action is proposed there are predictable consequences. I'm just putting them up for you to consider. Just another opinion. I certainly don't think it is"an emotional response with little basis in fact". Don't SHOOT the messenger...Nev

 

 

[Vev]

Talk about bases of fact ... when I spoke with Jab yesterday they informed me they will be paying for parts! You buy the parts on account and then you send back the old bits for a credit.

 

Cheers

 

Vev

 

 

[Jabiru Phil]

Talk about bases of fact ... when I spoke with Jab yesterday they informed me they will be paying for parts! You buy the parts on account and then you send back the old bits for a credit.Cheers

 

Vev

Thats what a 170 owner told me last night.

NO COST

 

 

[Vev]

I’m often amazed at the hostile reaction leveled at Jabiru when they are clearly trying to rectify an issue.

 

In my personal experience, they have always made every attempt to support any problem I have had… I have often received free or heavily discounted parts even though my aircraft is well out of its warrantee period…. I know many manufactures would simply send one to a call centre to chat with some dispassionate person on the other side of the planet.

 

I think we should be proud of what Jab have achieved as an Australian company and recognise their drive to keep on developing and improving.

 

It’s a small family company, not a global conglomerate, who do a fine job that deserves more support … they should be congratulated for listening and offering a solution.

 

Cheers

 

Vev